The invention relates to a double pulley device for use for Tyrolean traversing on a rope or cable comprising:
a pair of sheaves arranged in line inside a reverse U-shaped metal support flange-plate, each sheave being mounted rotating free on a fixed spindle of the flange-plate,
and means for fitting the flange-plate to an attachment snap-hook.
In double pulley devices used for Tyrolean or zip-line traversing, it is conventional to fit an attachment snap-hook in orifices situated at the bottom part of the flange-plate. The fixing point of the snap-hook is located under the point of contact of the sheaves with the cable. Fitting or removing the double pulley device necessarily requires the snap-hook to be removed, with risks of losing the pulley in the event of a handling error.
An object of the invention is to achieve a double pulley device that is easy to fit and remove and that provides maximum safety when used for Tyrolean traversing.
The device according to the invention is characterized in that the means for fitting the flange-plate comprise at least one orifice for passage of the snap-hook situated between the two spindles of the sheaves so that the fixing point of the snap-hook is positioned above the point of contact of the sheaves with the cable, one of the wings of the flange-plate being arranged to enable the mobile finger of the snap-hook to be opened when the double pulley device is fitted onto the cable.
According to a preferred embodiment of the invention, one of the wings of the flange-plate situated on the same side as the mobile finger of the snap-hook is shorter than the other wing. The two wings of the flange-plate are curved outwards to form a funnel enabling the cable to be fitted quickly on the sheaves. The bottom end of the longer wing is arranged as a stop for stable positioning of the snap-hook in a vertical position perpendicular to the flange-plate. The diameter of each sheave is larger than that of the orifices for passage of the snap-hook.
According to one feature of the invention, a deformable part is housed in the orifices to achieve captive fitting of the snap-hook.
According to another feature of the invention, the sheaves are fitted rotating on ball-bearings or self-lubricating bearings.